Artificial tooth for crowns and bridges.



No. 825,356. PATBNTBD JULY 10, 19 06.

W B. SHORT. I ARTIFICIAL TOOTH POR CROWNS AND BRIDGES.

APPLICATION FILED APR.8,1905.

WITNESSES: INVENTOIQ.

'UNITED STATES PATENT ()FFICE.

WILLIAM BYFEL'D SHORT, OF NEVV YORK, N. Y.

ARTIFICIAL TooTH FOR CRoyvNs AND BRI GES.

Specification of Letters Patent. Application filed April 8 1905. Serial lilo. 254,445

Patented July 10, 1906.

To all whom it may concern.

Be it known that I, WILLIAM 'BYFELD SHORT, a citizen of the United States, residtion.

mer is reduced to a minimum.

My invention relates to artificial teeth, and particularli to improvements in crown and )ridge wor It. consists, broadly, in the' means and method of attaching porcelain faces to backings, the urpose being to provide aconstruction of t e greatest possible strength, which will entirely eliminate-the necessity of pins or rivets and which will make it osslble to readilyrenew said orcelains in t e event of breakage without t 1e necessity of removing the backing. I

The invention is ap rior and posterior teet In the former the exposed or cutting edge of the tooth is porcelain, while in the latter the cusp is also of porcelain. The method of connecting each tooth to its support is such that the strains of occlusion are distributed uniformly over both the porcelain andthe backing, so that the danger of breaking or loosening the for- It will be seen also that the method of construction enables the practitioner to apply the tooth in any mouth no matter how close the bite may be. These and other advantages will be apparent to the experienced dentist.

In the drawings, Fi ure 1' is a front perspective view of a bri ge formed of my improved artificial teeth. Fig. 2 is a similar view, the porcelain faces being removed. Fig. 3 is a section on the line 3 3. Fi 4 is a view of the rear side of the porcelain acing shown in Fig. 3 detached. Flg. 5 is a section on the line 5 5. Fig. S isa view of the rear side of the porcelain faclng shown in Fig. 5 detached. 7 I will first describe the construction of the tooth shown in Figs. 5 and 6. In these views, 1 is the backing of such fo' rn as would be used in a bridge. 2 is the porcelain facing appropriate for the backing 1. 2 is the rearward extension on the porcelain facing 2. This extension is undercut on o' posite'sides so as to-form a dovetail, and this dovetailed ortion is adapted to fit into an o positelyormed cavity in the face of the bac ing. The dovetailed extension 2, on the rear of the lic able to both ante-- porcelain facing 2, is of nearl the same width as the extreme width of the tooth and of nearly the hei ht of the face of the backing. The dovetaile extension is also formed integrally with and on the orcelain. The width of the facin at the ottom of 'the groove formed by t e dovetailed extension should be from four to ei 'ht times the thickness of the extension. T e result is a substantial holding-surface is 'afiorded of such relatively great area-that the strains of occlusion. are distributed over the entire tooth. The dovetailed extension closely fits the cavity arranged to receive it inthe backing 1, and the same is held'in by the use of a suitable adhesive material. Because of the expansive area of the dovetailed portion I have found.

that not only is the tooth capable-of withstandingvery hard usage, but that by the use ofcement alone the facing 2 is firmly held against accidental displacement. vAs a result of my improvement, it is unnecessary to use any rivets or metallic conncctingieccs.

I am aware that heretofore metal ic pins and dovetails have been resorted to but never heretofore has a construction been provided in which the dovetailed connection was so formed relatively to the area of the tooth and the backing that metallic attachingpieces, such as pins orrivets, could be successfully eliminated. It has been found that when ins or metallic connecting-pieces are forrne with the porcelain facings microscopic fissures occur in the porcelain, which substantially weaken the same and render it liable to break. By my invention this is avoided. Now referring to Figs. 3 and 4, 1 represents the metallic backing in the form of a crown. 2* represents the porcelain facing, 2 representing .the dovetailed rear portion. In'this case, as in the former case, the dovetailed portion is formed integrally with the tooth and of only slightly less area than the rear of said casing. In this case the tooth is re resented as an anterior one, and one of the a vantages is that the cusp portion may be formed entirely of porcelain. 1 By m arrangement the old backing is practical y invisible, yet re' orces and su ports. the facing at all vulnerable oints. T 1e joint between the backing and t 1e inte ral extension of the facing comes substantialI tooth, so that there is little danger of accidental contact at this point, which would tend to break away the facing.

y at the edge of the In Figs. 1 and 2 I have shown a bridge in i I the bridge-teeth.

- which the two end teeth are crowns connect- It should be understood that the drawings are illustrativeirather than definitive save, of course; as to the means of connection.

It will be seen that in all cases the dovetailed portion is integral with theporcelain facing and is of but slightly less area than the rear surface of the same. a

What I claim is As an article of manufacture, an artificial tooth formed of two permanently-united I parts, a metallic backing part havin an out-' I wardly-protruding flange with slight y-taper- 1 [SEAL] ing sides and a connecting top continuous therewith formin a shallow cavity with undercut sides, am? a non-metallic facing of porcelain-like material having an extension at the rear of substantially the same width as its main portion and having a shallow groove extendingalong the sides and a shoulder across the top, the main portion extending above the shoulder, and an adhesive material permanently securing the extension of said facin in the cavity formed by the flanges and to of the backing, the joint between the bacliiing and the facing being substantially at the side edges and across the top of the extension a short distance top of the facing.

WILLIAM BYFELD SHORT.

Witnesses:

L. VREELAND, ROBT. S. ALLYN.

It is hereby certified that in Letters Patent N o. 825,356 granted July 10, 1906, upon the application of William Byfeld Short, of New York, l T. Y., for an improvement in Artificial Teeth for Crowns and' Bridges, an error appears in the printed specification requiring correction, as follows: In line 100; page 1, the word casing should read facing; a,nd that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Signed and sealed this 24th day of July, A. 1);, 1906. i

F. L ALLEN,

Commissioner ofPatents.

below the 5 I the bridge-teeth.

- which the two end teeth are crowns connect- It should be understood that the drawings are illustrativeirather than definitive save, of course; as to the means of connection.

It will be seen that in all cases the dovetailed portion is integral with theporcelain facing and is of but slightly less area than the rear surface of the same. a

What I claim is As an article of manufacture, an artificial tooth formed of two permanently-united I parts, a metallic backing part havin an out-' I wardly-protruding flange with slight y-taper- 1 [SEAL] ing sides and a connecting top continuous therewith formin a shallow cavity with undercut sides, am? a non-metallic facing of porcelain-like material having an extension at the rear of substantially the same width as its main portion and having a shallow groove extendingalong the sides and a shoulder across the top, the main portion extending above the shoulder, and an adhesive material permanently securing the extension of said facin in the cavity formed by the flanges and to of the backing, the joint between the bacliiing and the facing being substantially at the side edges and across the top of the extension a short distance top of the facing.

WILLIAM BYFELD SHORT.

Witnesses:

L. VREELAND, ROBT. S. ALLYN.

It is hereby certified that in Letters Patent N o. 825,356 granted July 10, 1906, upon the application of William Byfeld Short, of New York, l T. Y., for an improvement in Artificial Teeth for Crowns and' Bridges, an error appears in the printed specification requiring correction, as follows: In line 100; page 1, the word casing should read facing; a,nd that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Signed and sealed this 24th day of July, A. 1);, 1906. i

F. L ALLEN,

Commissioner ofPatents.

below the 5 

